A Virtual Cloud Network (VCN) is a customizable private network in Oracle Cloud Infrastructure.

Just like a traditional data center network, a VCN provides you with control over your network environment. This includes assigning your own private IP address space, creating subnets, creating route tables and configuring stateful firewalls. A single tenant can have multiple VCNs, thereby providing grouping and isolation of related resources.

One way to connect your on-premises network and your VCN is to use an Internet Protocol Security (IPSec) VPN. IPSec is a protocol suite that encrypts the entire IP traffic before the packets are transferred from the source to the destination.

In summary, the process for creating an IPSec VPN comprises the following steps:

1. Create your VCN.

2. Create a subnet in the VCN.

3. Create a Dynamic Routing Gateway (DRG).

4. Attach the DRG to your VCN.

5. Create a Customer Premises Equipment (CPE) object and provide your router's public IP address.

6. From your DRG, create an IPSec connection to the CPE object and provide your static routes.

7. Get the IPSec tunnel information

8. Configure the IPSec connection on the remote end.

9.  Create a route table and route rule for the DRG.

10. Create a security list and required rules.

     

Description of the illustration ipsec_for_vcn.png

To set up and manage an IPSec VPN for your VCN:

1. Sign in to the Oracle Cloud Infrastructure Console.
2. Create a VCN.
   1. Open the navigation menu, click Networking, and then click Virtual Cloud Networks.
   2. Click Create VCN.
   3. In the Create a Virtual Cloud Network dialog, enter a name for your VCN and select a compartment.
   4. Click Create VCN.
      Your VCN is created with some default components (default route table, default security list, default set of DHCP options).
3. Next, you’ll create subnets in separate Availability Domains. This allows distributing your instances across the subnets for high availability.
   1. In the Virtual Cloud Network details page, in the navigation pane, under Resources, select Subnets.
   2. Click Create Subnet.

      Enter the following details:

      Field	Description
      Name	Name of the subnet
      Availability Domain	Select an availability domain for your subnet.
      CIDR Block	Specify a CIDR block to indicate the network address that can be allocated to the resources.
      Route Table	Select a route table to provide mapping for the traffic from the subnet to destinations outside the VCN.
      SUBNET ACCESS	PRIVATE SUBNET: Select this option to prohibit public IP addresses for instances in the subnet. PUBLIC SUBNET: Select this option to allow public IP addresses for instances in the subnet.
      DNS HOSTNAMES IN THIS SUBNET	Select this option to allow assignment of DNS hostname when launching an instance.
      DNS LABEL	Auto-generated if no name is specified.
      DNS DOMAIN NAME	Read-only field
      DHCP OPTIONS	Select the DHCP option for the VCN.
      Security Lists	Specify security list/s for the VCN.

   3. Click Create.
4. Create a Dynamic Routing Gateway (DRG) to provide a path for private network traffic between your VCN and on-premises network.
   1. Open the navigation menu and click Networking. Under Customer Connectivity, click Dynamic Routing Gateway.
   2. Click Create Dynamic Routing Gateway.
   3. Specify a compartment, enter a name for the DRG and click Create.
5. Once the Dynamic Routing Gateway is created, you can attach it to your VCN.
   1. Open the navigation menu, click Networking, and then click Virtual Cloud Networks.
   2. Click your VCN to open its details.
   3. In the Virtual Cloud Network Details page, in the navigation pane, under Resources, click Dynamic Routing Gateways.
   4. Click Attach Dynamic Routing Gateway.
   5. Select the dynamic routing gateway that you created and click Create.
6. After attaching the Dynamic Routing Gateway to your VCN, create a Customer Premises Equipment (CPE) to logically represent the on-premises VPN device within Oracle Cloud Infrastructure networking configuration.
   1. Open the navigation menu, and click Networking. Under Customer Connectivity, click Customer-Premises Equipment.
   2. Click Create Customer-Premises Equipment.
   3. Select the compartment, enter a name and IP address for the customer-premises equipment, and click Create.
7. Next, create an IPSec connection to the customer-premises equipment.
   1. Open the navigation menu and click Networking. Under Customer Connectivity, click Dynamic Routing Gateway.
   2. Click the dynamic routing gateway that you created.
   3. In the Dynamic Routing Gateway details page, in the navigation pane, under Resources, click IPSec Connections.
   4. Enter a name and public (external) IP address of the VPN device to be used to establish IPSec VPN and click Create.
   Once the IPSec connection is created , Oracle Cloud Infrastructure creates IPSec tunnel endpoints in each availability domain. You can use the tunnel information to configure the on-premises VPN device.
8. Get the IPSec tunnel information. Select the IPSec Connection and click Tunnel Information. The tunnel information contains the IP addresses of the tunnel endpoints and the shared secret to be used to initiate the IPSec connection. It also shows the status of the IPSec connection.
9. Configure the IPSec connection on the remote end. Your network administrator can configure your on-premises VPN device(s) to initiate an IPSec connection to the tunnels created on Oracle Cloud Infrastructure.

   Note:

   It is recommended to establish at least two IPSec tunnels, from the on-premises VPN device.

10. Configure routing for subnets to go through Dynamic Routing Gateway for on-premises traffic. The default routing table created for a VCN has no rules by default. All instances in VCN have a route to other instances in the VCN only.
    1. Open the navigation menu, click Networking, and then click Virtual Cloud Networks.
    2. Click the VCN to open its details.
    3. In the Virtual Cloud Network details page, in the navigation pane, under Resources, select Route Tables and then click Edit Route Rules.
    4. Modify the default route table to add a default route and set the Dynamic Routing Gateway as the route target. This routes any non-VCN traffic through the Dynamic Routing Gateway into the on-premises network.
11. Configure security rules to allow valid traffic in/out of your subnets.
    1. Open the navigation menu, click Networking, and then click Virtual Cloud Networks.
    2. In the Virtual Cloud Network details page, in the navigation pane, under Resources, select Security Lists.
    3. Select the security list for your VCN and click Security List Details.
    4. The default security list has only three ingress rules and one egress rule to allow all outgoing traffic. Click Edit All Rules to modify the rules to allow SSH as required and to open up specific ports for the application running on your compute instances within the subnets.